Research Of Early Warning Technology Of Water Inrush In Coal Mine By Stress-water Coupling Effect

Water inrush is a major hazardous accident in coal mine production, and also a serious threat to safety. The main research of this paper includes following three aspects: the weak rule and the permeability characteristics of coal and rock mass that meets water under the stress field, during the process of mining what the range and diffusion law does the water have about affecting the coal and rock mass, and the application of warning technique that based on the weak rule, permeability characteristics and affected range.This test use the triaxial test machine, as the research shows that briquette specimen could be a substitute for raw coal, so all specimen are briquette specimen, and the whole test included two parts. Analysis how the briquette specimen are influenced by water to study the weak rule; control input water pressure, confining pressure and axial compression, keep single factor changes while triaxial tests to research on the permeability. The weak rule test divided the specimen into three groups, respectively, for unprocessed, half saturated water and saturated water. The test include two parts, the first is complete stress-strain test, second is step loading test. The result shows that water has significant impact on specimen. Mainly,the maximum axial of coal and rock and compressive strength is significantly reduced, and after the peak damage loading capacity reduced. The result of permeability shows that the permeability increases with the water pressure increased, if confining pressure increased then permeability decreases, axial compression makes the permeability of coal briquette specimen first decreases then increases.Based on the fluid percolation theory, especially the Darcy’s law, study on the scope of influence about water on water barrier. Chose goaf water as the research object, used COMSOL. Through the analysis of numerical simulation, it showed three results.(1) during permeation process of water, center on the area of goaf water, the nearer the more serious influence on water barrier, whereas the smaller the influence;(2) penetration area expanded with more time went on and greater water pressure, furthermore, the amount of the affected area increases bigger and bigger;(3) only when water pressure reach a higher level, the water are more likely spread to space direction which has no other constraints.Based on the weak rule, permeability characteristics and affected range, an early warning system is designed in theory. The main monitoring parameter of this system is pressure and permeability, include change curve and the average safety deviation totally fiveitems. Use the weight function of each monitoring item with AHP, grade each item, and then calculate the total safety index. Define which area belongs to, and enforce the corresponding measures. At last, described the prevention priorities of water inrush accident from safety technique and safety management.